So does this mean that Europeans only need to buy half as much weed as they did a decade ago?

A study tracking increased potency of both herbal and resin types of the drug points to greater dangers for usersCannabis potency has doubled across Europe in the past decade, according to the first study to track changes in the drug across the continent.

The study, published on Sunday in the journal Addiction and conducted by researchers from the University of Bath and King’s College London, finds that both cannabis resin and herbal cannabis have increased in strength and price with potentially harmful consequences for users.